Riello DB3 SM C03 Installation, Use And Maintenance Instructions page 54

5.7 Flame sensor disassembly and
maintenance
The flame sensor is fixed to the burner by a bayonet connection.
If it needs removing for cleaning, it should be turned by 1/8 in an anti-clock-
wise direction and then removed.
 Working with pre-heated combustive air.
Sensitive element disassembly
If the sensitive element in the sensor needs replacing, proceed as follows:
1 remove the four fixing screws from the rear cover and then remove the
cover;
2 remove the sensitive element support;
3 remove the sensitive element from the fixing plate;
4 install a new element on the plate, avoiding direct contact with the
hands;
5 refit the sensitive element support and the sensor cover.
5.8 Checking the flame detector
Flame sensor
Minimum current for correct working is 70 µA. If the value is lower, it could be due to:
• exhausted sensor;
• low current (lower than 187 V);
• bad regulation of the burner.
In order to measure the current, use a microammeter of 100 A c.c., connected in series to the sensor, as in the scheme, with a
capacitor of 100 F - 1V c.c. at the same level of the instrument.
24
5
CHAPTER Preparation for start up
attachment (Rp 1/4)
P max. 50 mbar
D2143
Extraction
D1143
D2142
 Cooling air
Fig. 30
Assembly
Fig. 31
Fig. 32